ASI Safety Tip: More than you asked for

One experienced an engine flameout north of Savannah, Georgia, and then lost its second engine. The other experienced an engine failure en route to Chicago.

Both Citations landed safely, but the incidents highlighted a risk of fuel contamination that turbine pilots should be aware of: Diesel exhaust fluid (DEF), a colorless additive used with diesel engines to reduce emissions, has been added mistakenly to jet fuel on three occasions over the past 18 months. Presumably, operators have mistaken DEF for fuel system icing inhibitors (FSII), which are also colorless. The AOPA Air Safety Institute offered this advice to turbine aircraft operators in a safety notice:

What you should do

• Talk with your fuel providers and ask if they use DEF in ground equipment. If so, inquire about procedures to confirm correct additives are used for jet fuel. This should include separate storage, clear labeling, confirmation of correct additives at the time of insertion, and training for personnel.
• DEF crystallizes in jet fuel and clogs fuel filters, which can result in fuel starvation. If engine failure occurs due to turbine flameout, be cognizant of the potential for DEF contamination. Follow emergency checklist procedures for engine failure and realize if DEF contamination is the cause, successful restart is unlikely.
• If a turbine engine flameout occurs in a multiengine aircraft, follow emergency checklist procedures and expect loss of the remaining engine(s). Consider preserving altitude for as long as possible to maximize potential of a safe glide to a suitable runway.
• If you encounter or suspect any DEF contamination, notify the fixed base operator where fuel was obtained as soon as possible. Document the incident and report it to the local FAA flight standards district office (FSDO) immediately.

What you should know

• There are no known preflight procedures pilots can use to identify the presence of DEF in jet fuel.
• An industry working group, which includes AOPA, is working to understand causes of contamination and provide recommendations for prevention.